The invention relates to a video signal transmitting apparatus for inputting a video signal output of a video signal source, processing the video signal, and outputting to a displaying apparatus.
An example of a video signal transmitting apparatus for video-compressing a video signal of a video signal source and, thereafter, radio-transmitting to a displaying apparatus has been disclosed in JP-A-2004-165921.
As a digital video interface between apparatuses, there is an HDMI (High-Definition Multimedia Interface) disclosed in “High-Definition Multimedia Interface Specification, Informational Version 1.0, HDMI, LLC, USA, 2003 Sep. 4”. In the HDMI, a CEC (Consumer Electronics Control) has been determined as a communication specification between the apparatuses using lines in an HDMI cable. An example of making control between the apparatuses by using a CEC message for transferring control information and apparatus information of the connected apparatus in the CEC standard has been disclosed in JP-A-2007-214952.
In the HDMI, such a technique that the video signal source reads EDID (Extended Display Identification Data) information showing display ability and specification of a video displaying apparatus and selects a format of an output video signal has been disclosed in “A DTV Profile for Uncompressed High Speed Digital Interfaces CEA-861B, Consumer Electronics Association, USA, May 2002”. Such a technique that as timing when the signal source reads the EDID information, an HPD (Hot Plug Detect) signal in which a state where the cable has been connected is shown by a logic level “H” is used and such timing is set to timing after the logic level was changed from “L” to “H” has been disclosed in “High-Definition Multimedia Interface Specification, Informational Version 1.0, HDMI, LLC, USA, 2003 Sep. 4”. By using those mechanisms, the specification of the video displaying apparatus can be transferred to the video signal transmitting apparatus and the specification of the video signal transmitting apparatus can be transferred to the video signal source.